While most information-theoretic security works to date have revolved around the issues of protecting the content of information, the growing concern around mass communication surveillance programs has reignited interest in investigating the covertness of communications, also known as low probability of detection (LPD), in which covertness requires that the communication remains undetectable from a watchful adversary, named warden. The concept of covert communication has shown tremendous research value and application value [1]}, [2]}. In the covert communication scenarios, the transmitter (Alice) possesses sensitive information that needs to be sent to the legitimate receiver (Bob), while the warden (Willie) listens to the communication environment and tries to detect any covert transmission from Alice to Bob with some probable existed uncertainties. These uncertainties can be formed from Willie's receiver noise power, imperfect channel knowledge, finite blocklength, and interference from other network users or artificial noise.
